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3uz7
From Proteopedia
Contents |
Crystal structure analysis of ribosomal decoding. This entry contains the 30S ribosomal subunit of the second 70S molecule in the asymmetric unit for the cognate tRNA-tyr complex.
During protein synthesis, the ribosome accurately selects transfer RNAs (tRNAs) in accordance with the messenger RNA (mRNA) triplet in the decoding centre. tRNA selection is initiated by elongation factor Tu, which delivers tRNA to the aminoacyl tRNA-binding site (A site) and hydrolyses GTP upon establishing codon-anticodon interactions in the decoding centre. At the following proofreading step the ribosome re-examines the tRNA and rejects it if it does not match the A codon. It was suggested that universally conserved G530, A1492 and A1493 of 16S ribosomal RNA, critical for tRNA binding in the A site, actively monitor cognate tRNA, and that recognition of the correct codon-anticodon duplex induces an overall ribosome conformational change (domain closure). Here we propose an integrated mechanism for decoding based on six X-ray structures of the 70S ribosome determined at 3.1-3.4 A resolution, modelling cognate or near-cognate states of the decoding centre at the proofreading step. We show that the 30S subunit undergoes an identical domain closure upon binding of either cognate or near-cognate tRNA. This conformational change of the 30S subunit forms a decoding centre that constrains the mRNA in such a way that the first two nucleotides of the A codon are limited to form Watson-Crick base pairs. When U.G and G.U mismatches, generally considered to form wobble base pairs, are at the first or second codon-anticodon position, the decoding centre forces this pair to adopt the geometry close to that of a canonical C.G pair. This by itself, or with distortions in the codon-anticodon mini-helix and the anticodon loop, causes the near-cognate tRNA to dissociate from the ribosome.
A new understanding of the decoding principle on the ribosome., Demeshkina N, Jenner L, Westhof E, Yusupov M, Yusupova G, Nature. 2012 Mar 21. doi: 10.1038/nature10913. PMID:22437501
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
About this Structure
3uz7 is a 25 chain structure with sequence from Escherichia coli and Thermus thermophilus. Full crystallographic information is available from OCA.
See Also
- Ribosomal protein S10
- Ribosomal protein S11
- Ribosomal protein S12
- Ribosomal protein S13
- Ribosomal protein S14
- Ribosomal protein S15
- Ribosomal protein S16
- Ribosomal protein S17
- Ribosomal protein S18
- Ribosomal protein S19
- Ribosomal protein S2
- Ribosomal protein S20
- Ribosomal protein S3
- Ribosomal protein S4
- Ribosomal protein S5
- Ribosomal protein S6
- Ribosomal protein S7
- Ribosomal protein S8
- Ribosomal protein S9
- Ribosomal protein THX
Reference
- Demeshkina N, Jenner L, Westhof E, Yusupov M, Yusupova G. A new understanding of the decoding principle on the ribosome. Nature. 2012 Mar 21. doi: 10.1038/nature10913. PMID:22437501 doi:10.1038/nature10913
Categories: Escherichia coli | Thermus thermophilus | Demeshkina, N. | Jenner, L. | Yusupov, M. | Yusupova, G. | Mrna | Ribosome | Rna | Translation | Trna
